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Q1. | The power is measured in terms of decibles in case of |

A. | Electronic equipment [Correct Answer] |

B. | Transformers [Wrong Answer] |

C. | Current transformers [Wrong Answer] |

D. | Auto-transformers [Wrong Answer] |

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Explanation:-
Answer : ADiscuss it below :!! OOPS Login [Click here] is required to post your answer/resultHelp other students, write article, leave your comments |

**Also Read Similar Questions Below :**

⇒ The ratio of the bandwidth to the resonance frequency is called the____ of the circuit.

Impedance

Susceptance

Quality factor

Selectivity

⇒ Which of the following waves has the highest value of peak factor '?

Square wave

Sine wave

Half wave rectifier sine wave

Triangular wave

⇒ The shunt element of prototype high pass filter is

Resistive

Inductive

Capacitive

Combination of L and C

⇒ Which of the following statement is incorrect ?

Resistance is a passive element

Voltage source is an active element

Conductance is a passive element

Current source is a passive element

⇒ Form factor for a sine wave is

1.414

0.707

1.11

0.637

⇒ Poor power factor results in all of the following EXCEPT.

Overloading of transformers

Overloading of altemators

Reduction in power losses

Reduction in load handling capacity of electrical system

⇒ Power factor of an inductive circuit is usually improved by connecting capacitor to it in

Parallel

Series

Either (A) or (B)

None

⇒ The period of a wave is

The same as frequency

Time required to complete one cycle

Expressed in amperes

None of the above

⇒ In A.C. circuit the power curve is a sine wave having

Double the frequency of voltage

Same frequency as that of voltage

Half the frequency of the voltage

None of these

⇒ A sine wave of voltage varies from zero to maximum of 200 V. How much is the voltage at the instant of 30° of the cycle ?

50V

82.8V

100V

173.2 V

⇒ A parallel resonant circuit can be used

As a high impedance

To reject a small band of frequencies

Both (A) and (B)

To amplify certain frequencies

⇒ Capacitive reactance is more when

Capacitances is less and frequency of supply is less

Capacitance is less and frequency of supply is more

Capacitance is more and frequency of supply is less

Capacitance is more and frequency of supply is more

⇒ Which of the following is not a non-linear element ?

Transistor

Heater coil

Diode

Electric arc with unlike electrodes

⇒ If resistance is 20 ω and inductance is 2H in a RL series circuit, then time constant of this circuit will be

0.001 S

0.1 S

10 S

100 S

⇒ For a sine wave with peak value I

_{max}the r.m.s. value is

0.5 I

_{max}

0.707 I

_{max}

0.9 I

_{max}

1.414 I

_{max}

⇒ Power factor of electric bulb is

Zero

Lagging

Leading

Unity

⇒ A resonance curve for a series circuit is a plot of frequency versus

Current

Voltage

Impedance

Reactance

⇒ Power factor of the following circuit will be unity

Inductance

Capacitance

Resistance

Both (A) and (B)

⇒ Capacitors for power factor correction are rated in

kW

kVA

kV

kVAR

⇒ The power consumed in a circuit element will be least when the phase difference between the current and voltage

180°

90°

60°

0°

⇒ Ohm is the unit of all of the following except

Inductive reactance

Capacitive reactance

Resistance

Capacitance

⇒ Form factor is the ratio of

Average value/r.m.s. value

Average value/peak value

r.m.s. value/average value

r.m.s. value/peak value

⇒ In a parallel R-C circuit, the current always ____the applied voltage.

Lags

Leads

Remains in phase with

None of the above

⇒ All the rules and laws of D.C. circuit also supply to A.C. circuit containing

Capacitance only

Inductance only

Resistance only

All above

⇒ While drawing vector diagram for a series circuit the reference vector is

Voltage

Current

Power

Phase angle

⇒ The r.m.s. value and mean value is the same in the case of

Triangular wave

Sine wave

Square wave

Half wave rectified sine wave

⇒ At half power points of a resonance curve, the current is____ times the maximum current.

1/2

1/ √2

√2

2

⇒ The power factor of a series R-L-C circuit at its half-power points is

Unity

Lagging

Leading

Lagging or leading

⇒ Two sinusoidal quantities are said to be phase quadrature, when their phase difference is

0

30°

45°

90°

⇒ The product of apparent power and cosine of the phase angle between circuit voltage and current is

True power

Reactive power

Volt-amperes

Instantaneous power